A metal composite produced by laminating a metal material and a fiber-reinforced resin material and bonding them together combine homogeneous strength and elastic modulus, excellent impact resistance, thermal conductivity and other characteristics provided with a metal and excellent lightweightness, specific strength, specific modulus, anisotropy of reinforcement according to fiber direction and other characteristics provided with a fiber-reinforced resin. For this reason, they are used in a variety of applications, including aircraft body parts, motor vehicle body parts, marine vessel parts, machine mechanical parts, golf clubs, and parts of notebook computers, video cameras and other electronic equipment (see patent documents 1 to 5).
Conventionally, it has generally been the case that, when producing such a metal composite, a metal material is first molded into a predetermined shape, and then reinforcement fibers impregnated with a thermosetting resin are placed in contact with the metal material, followed by curing of the thermosetting resin to form a fiber-reinforced resin material that integrates with the metal material. In patent document 4, for instance, a composite structural material comprising a metal and fiber-reinforced resin is produced by injecting reinforcement fibers and thermosetting resin into a molded metal pipe and curing the thermosetting resin.
Similarly, it has also generally been the case that, when producing a metal composite in which two or more metal materials are bonded by means of a thermosetting resin, the metal materials are first molded into their respective predetermined shapes and then the thermosetting resin is placed between the metal materials, followed by the curing of the thermosetting resin to bond those metal materials.
However, such a manufacturing method is problematic in that it separately requires a metal material molding step and a molding step for whatever other structural material to be composted with the metal material, resulting in a low composite production efficiency. Furthermore, since a thermosetting resin is introduced after a metal material has been molded into a complex shape, it is difficult to guarantee that the required bonding strength is provided in the manufacturing process, and, for this reason, there is a risk that, if, for instance, a thermosetting resin is not adequately placed, even if only in parts, problems such as the flaking of the metal composites arise during use.
Also conventionally, it has generally been the case that, with metal composites for electronic equipment chassis, a resin that serves as a binder layer between the metal material and the fiber-reinforced resin is placed to integrate them. Patent document 1, for instance, discloses a configuration that incorporates an intermediate resin layer containing thermoplastic resin particles to improve the bonding strength between the metal material and the fiber-reinforced resin. Even with regard to the shaping of a metal composite, it has generally been the case that, when a complex shape is required, the metal material is processed to the desired shape in advance through press molding or punch molding before it is integrated with the fiber-reinforced resin (patent documents 6 and 7).
Furthermore, since such electronic equipment chassis require a resin layer aimed at providing bonding, there is deficiency in the amenability to thin-wall design and degree of design freedom, and this has given rise to the problem of undermining the ongoing efforts to reduce the weight of electronic equipment. There is another problem in that, since separate processing steps are required for the metal material and fiber-reinforced resin, the production cost of chassis is high due to a need for a large amount of production equipment needed.